The relationship between human migration and the spread of infectious diseases has been well documented throughout human history. However, since the advent of intercontinental air travel in the 20th century, a massive, continuously expanding and evolving global airline transportation network has emerged to meet the world's surging demand for mobility. Concurrently, an explosion in global population has resulted in rising numbers of people traveling across greater distances in shorter and shorter time periods. Presently, the global airline transportation network carries more than two billion passengers per year. While the global airline transportation network has created a more interconnected world, it has also evolved into a major conduit for the spread of potentially dangerous infectious agents.
FIG. 1 demonstrates the evolution of global factors contributing to emergence and spread of infectious diseases. During the past century, global population growth has surged, reaching an estimated 6.7 billion people worldwide in 2008. Since the advent of intercontinental commercial aviation in the mid 20th century, the time required for an individual to circumnavigate the globe has dropped precipitously, reaching less than 24 hours—shorter than the minimum incubation period for most human infectious diseases. Moreover, the phenomenon of global warming contributes to the expansion of ecological niches for important infectious disease vectors such as ticks and mosquitoes, which in turn is conducive to the emergence and reemergence of infectious diseases in human populations. Recognition of this “perfect storm” is growing, as documented in the 2007 World Health Report on Global Public Health Security in the 21st century ISBN 978 92 4 156344 4. The report indicates that since the 1970s, new infectious disease threats have emerged at an unprecedented rate of one or more per year and that “Infectious diseases are now spreading geographically much faster than at any time in human history” [quote from Dr. Margaret Chan, Director General of the World Health Organization].
The emergence in 2003 of severe acute respiratory syndrome (SARS) and its subsequent dissemination via commercial aircraft to twenty-six countries on four continents provided irrefutable evidence that international and even intercontinental borders are highly permeable to the spread of infectious diseases. Post-SARS, confirmed human cases of avian H5N1 influenza across Asia and Africa have raised concerns that an influenza pandemic could be imminent. After the intentional spread of anthrax spores via the United States postal service in 2001, speculation over the intentional release of smallpox virus sparked additional fears of a pandemic. Whether originating from breaches at laboratories harbouring dangerous infectious pathogens, bioterrorism, or natural causes, outbreaks of emerging diseases with pandemic potential constitute a vital threat to the health and economic security of the entire international community.
Despite the role of commercial aviation as a major vehicle for the spread of emerging infectious diseases, knowledge of the global airline transportation network and its relationship to global security and public health remains extremely limited to date. Yet there is evidence to suggest that in today's world, the international and intercontinental spread of infectious diseases will occur predominantly via commercial air travel, and that the trajectories with which the disease will spread are, to a large extent, predictable. As proof of principle, a remarkably predictable relationship was identified between the structure of and flow of passengers on the global airline transportation network and the observed international spread of the SARS coronavirus in 2003. This association, observed during an outbreak that has been frequently dubbed a “pandemic dress rehearsal”, inspired the development of further research converging expertise in medicine, infectious diseases, statistics and mathematics, networks, geography, and computer sciences. Consequently, an invention was needed to provide governments, businesses, and other organizations with the information necessary to fully appreciate their vulnerabilities in a highly interconnected and interdependent world. More importantly, a need was identified to rapidly generate evidence-based strategic plans to mitigate the risks associated with dangerous global infectious disease threats, and to do so in a manner that is uniquely tailored to the stated needs and global “footprint” of a given client at any specified point in time.
It is an object of this invention to partially or completely fulfill one or more of the above-mentioned needs.